Insulator



(NorModel.) 2 Sheets-Sheet 1.

L. MGGARTHY. INSULATOR.

No. 449,943. Patented Apr. '7, 1891.

@ Q/Mm, V Z Muna? VEA/75E.

(No Model.) 2 Sheets-Sheet 2.

1 L. MGGARTHY. INSULATOR.

No. 449,943. Patented Apr. '7, 1891.

MTA/5555. I /V-/V TUR- @MA l (4.4.14 d M 5,7%

Tn: cams uns co4. moro-mno., wnsmnnron, n4 c,

UNITED STATES PATENT OEEIcE.l

LOUIS MCOARTHY, OF BOSTON, MASSACHUSETTS.

INSULATOR.

SPECIFICATION forming part of Letters Patent No. 449,943, dated April 7,1891.

Application filed January 16, 1891. Serial No. 377,982. (No model.)

To @ZZ whom t may conceive:

Be it known that I, LOUIS MCCRTHY, of Boston, county of Suifolk, Stateof Massachusetts, have invented certain new and useful Improvements inInsulators, of which the following` is a specification, reference beinghad to the drawings accompanying and forming a part hereof, in which 1have shown inyinvention in the best form now known to me.

Figure 1 is a section showing` my invention embodied in a line-insulatorfor electric-railway purposes. liig. 2 is a section on line 2 2, Fig. 1.Fig. 3 is a section showing myinvcntion as embodied in a pull-ottinsulator for electric railways. Fig. el is a section showing myinvention as embodied in an insulator for gasaliers or combinedgasaliers and electroliers. Fig. 5 is a plan view of the device shown,Fig. et.

My invention has for its object an insulator for electrical purposeswhich shall be cheap, durable, strong, and ei'lic'ent; and it consistsof an insulator the metallic or conductive parts of which are separatedby layers or sheets of mica laid together, as hereinafter set forth, andas is more particularly pointed out in the claim which is appendedhereto, and which forms a part hereof.

My improved insulator is simple and easily constructed, and will bereadilyunderstood from the following description.

A is a bell-shaped piece of metal or other suitable material such as iscommonly employed forline-insulators. The upper portion or cap a of thebell is adapted to be screwed into the lower portion, as shown.' To thecap arms or other projections may be secured, by means of which theinsulator is held in place in the well-known manner. The bell below thecap is hollow and is provided at '0 with a iiange or rib projectinginwardly, as shown. The bolt (l, having a head of any desired shape7 isprovided with a number of layers or sheets of mica, each of which isperforated to receive the bolt, a sufficient number of sheets being usedto fully insulate the head of the bolt from the bell. The cap a beingremoved, the bolt and the sheets of mica are then placed in the bell,the mica resting on the [iange l). Other pieces of mica of the rightshape and having a perforation or hole therein correspondingin size andshape to the head of the bolt are then placed in the bell around thohead of the bolt, a sufiicient numberof sheets being used to fill up thespace around the sides of the bolt-head to a level with the top thereof.The space above the bolt-head is then filled with other sheets of micacut to proper size to fit snugly the inside of the bell, a sufficientnumber of sheets being used to fill the space between the top of thebolt-head and the cap a. The sheets of mica are thoroughly compressedand compacted either before insertion or afterward, forming a solid massof great strength and durability and of high insulating quality. The capis then screwed on and the insulator is ready for use. As will beObvious, the size and shape of the part-s may be changed, so as to givea greater or less thickness of insulating material between the bolt dand the bell and to adapt the shape and size of the device totheconditions under which it is to be used. The skirt of the bell isallowed to project downwardly t0 shed the moisture, and in this way aninsulator of great excellence and durability is produced.

At Fig. 8 1 have shown a modification of my insulator adapted for use asa pull-off insulator. The construction is, however, substantially thesame, as will be obvious, with the exception of the addition of a secondflange or inward projection f out-side of the projection Zi, whichserves to more effectually shed the moisture when the device is used ina horizontal or substantially horizontal position, as is generally theease with pull-off insnlators.

As will be clear, my device may be readily adapted to insulators ofother forms and for other purposes than those above mentioned.

At Fig. a I have shown an insulator for gasaliers, which may be used toinsulate the gasalier from the gas-supply pipe in cases where thegasalier is also provided with electric lights or insulation for anypurpose is desired. In this case the bell-shaped case is changed inform, and consists, simply, of two caps or frames g 7L, which serve tohold the layers of mica together by the aid of the bolts 7a, which passthrough the caps and through the mica. The pieces Z, which correspondwith the b olt d, have an aperture m through them, and there is acorrespondin aperture through the IOC central portion of the mica, asshown at p, so that the gas may pass from the pipe to the gasaler. Thepiece marked l, Fig. 4, and the bolt d, Fig. l, are merely forms of themetallio connection or support which is insulated and the precise shapeof which Will depend on the purposes for which the insulator is to thepieces Z. Then such means are used, less pressure is necessary in firmlysetting the sheets of mica together. The cap d, Figs. l and 3, is shownand I have described it as screwed onto the bell or holder A. It will beobvious, however, that it may be secured to the bell in any otherWell-known Way.

Vhat I claim is- An insulator comprising a bell or case adapted to holda series of sheets of mica, a metallic supporting-piece placed therein,and a series of sheets of mica/.surrounding said piece and adapted toinsulate the same from said bell or case, substantial-ly as and for thepurposes set forth.

LOUIS MCCARTHY.

Witnesses:

ROBERT WALLACE, C. E. NoL'rE.

